Mechanism for power transmission



May 26, 1953 M. TAYLOR f 2,639,631

' MECHANISM FORPOWERYTRANSMISSION- Filed April 8,' 195o 2 Sheets-Sheet lM8126 1953 M. TAYLOR i I 2,639,631

MCHANISM FOR POWER TRANSMISSION Filed April 8, 1950 2 Sheets-Sheet 2. .f

l \NVENTOR'.

Patented May 26, 1953 UNITED STATES eATENT oppicg MECHANISM FOR POWERTRANSMISSIGN Marvin Taylor, Brooklyn, N. Y.

Application April 8, 1950, Serial No. 154,768

(Cl. '14a-751) 7 Claims@ l This invention relates to power transmissiondevices in which gy'roscopic forces are utilized to produce a resultanttorque on a driven shaft.

Many attempts have been made to invent an etiicient mechanical powertransmission that could successfully be used between a consi-,ant speedpower source and a variable speed load for appreciable magnitudes ofpower. I am aware that a number of devices claiming to utilizegyroscopic forces to accomplish the above purpose have been patented.Most of those devices which truly use a gyroscopic torque have beenfaced with the same problem, namely, after a spinning; flywheel has beenprocessed 180, there is a change in the direction oi the gyroscopictorque that is developed. Previous devices have attempted to overcomethis reversal by allowing the gyroscope flywheel to tui-n about fouraxes, namely, the spin axis, the procession airis, the power axis, and afourth axis which keeps the output torque unidirectional. This leads toa complex mechanism which cannot practically deliver appreciable powerin a machine ol usable size. Furthermore, this complexity leads to aprohibitive manufacturing cost. My invention utilizes the gyroscopictorque in a simple, rugged mechanismy by decreasing the flywheel spinspeed during the portion of the procession cycle when the direction ofthe developed torque is opposite to desired direction. Hence, a numberof flywheels, each producing an oscillating torche which is greater inone direction, can be combined to produce a constant unidirectionaltorcido as will be explained in the discussion which follows.

The object of this invention is to provide e. simple, enicient,l anddurable mechanism for transmittini;y power from a constant speed powersource, said mechanism beine capable of the followingv properties:l

i. Complete control ci the torque on the driven shaft independent of thespeed of the driven shaft which may vary within wide; limits.

2. Automatic and continuous vaifizttioii of torque on the driven shaftto accommodate changes in load regardless ci the speed or the drivenshaft which may'y vary within wide iiiiiii-s.

Preferred embodiments of my invention: ll be described with reference tothe accompanying drawings iorming a part ot this speciiication inuf'hfih Figures 1.a-, lli,.- lc, and ld are explanatory dian grams oi'a. gyroscope carried tlv ai driven shaft, in ioni' positions, means formaintaining: iivwlieei spin and procession being omitted.

Figures 2a, 2b, and 2c are explanatory graphs illustrating the relationbetween torque on the driven shaft and gyroscope position for differentsituations.

Figure 3 is an eimlanatory` diagram showing three flywheels beingcarried by 'a driven shaft, means for maintaining 'procession being'omitted.

Figure 'l is a part=s`ectional plan of e preferred embodiment.

Figurey 5 is a partesectional elevation along line 5--5 in Figure 4,omitting gear 52.

Figure 6 is a part-sectional plan of another preferred embodiment.

In Figures la, 1b, 1c', and 1d, a driven shaft 3 has rigidly attached toit a gimbal 2 in which is pivoted a ring l' which is free to rotateabout an axis at right angles to the axis, of the shaft 3. A flywheel 4is free to spin in bea-ringo in the ring I', the axis of spin being atright angles to the axis about which ring I turns in gimbal 2. The axisof flywheel spin within ring l" will be known as the spin axis. The axisof rotation of the flywheel supporting memberi ring I', Within gimbal Zwill be known as the procession axis. The axis of rotation of glmbal 2and driven shaft 3 is the power axis. The. spin, precession, and poweraxes cross each other substantially at a common point in the center offlywheel 4. It will be assumed that ywheol 4' is drivenat constant speedin the direction shown by the arrow on it and that the ring l is to berotated about the precessionaxis at a, constant speed in the directionas indicated by the arrow by suitable means not showni Figuresy la, 1b,le, and ld show consecutive positions as ring if is rotated about. theprocession axis while the drivenshaft is held stationary by means notshown.- The lotation of ring l carrying with it the spinning flywheel4.' will develop a gyroscopic torque about the power axis' in thedirections indicated by the arrows n the different diagrams. In Figurela, the spin axis is at a right angle to the power axis.y In Figure 1b,the ring I" carryingA the flywheel 4 has rotated QO from its( positionin Figure' 1d so that the spin axis and the power' axis are cio-linear;in Figure lo, ring. l and the flywheel have rotated 186 from theirposition iii Figure la; and in Figure ld, ring l and theywheel haverotated 270 from their lOS'itil irl. Figure la.

At any position during the procession cycle, the gyroscopio torqueabout. the power axis. will be a function of the procession speeld ondthe ngular momentum of the flywheel about the xls which is perpendicularto the pow'i and predes- `power axis. 'and that in Figure 1d, themagnitude of this be less. of the precession cycle when thetorque isposi" sion axes. In Figures 1a and 1c, this component of angularmomentum is maximum in opposite directions, and in Figures 1b and 1d,this component is zero.

In Figure la, the rotation of the spinning flywheel 4' about theprecession axis develops a torque about the power axis as shown by thearrow in a direction which may be called positive. As the fdywheelapproaches the position in Figure 1b, the component of angular momentumperpendicular to the power axis decreases to zero, hence the torquedeveloped about the power axis decreases to zero. As the flywheel movesfrom the position in Figure 1b to that in Figure lc, a negative torqueis developed about the power axis, i. e., in a direction opposite tothat developed in Figure la. This negative torque is maximum at theposition in Figure lc, when the spin axis is again at a right angle tothe Between the position in Figure lc negative torque decreases to zero.Between the position shown in Figure 1d and that in Figure la, thetorque becomes positive, increasing to a .maximum at the position inFigure 1a. The nature of this variation of gyroscopic torque about .thepower axis with position of the flywheel about the precession axis isshown inthe graph in Figure 2a in which the ordinate is gyroscopictorque about the power axis and the abscissa is displacement about theprecession axis.

As previously stated, the magnitude of the gyroscopic torque isdependent upon a component of the angular momentum of the iiywheel whichis :the product of the spin speed and the flywheel moment of inertiaabout the spin axis. It will,

-therefore, be possible to change the form of the torque variation shownin Figure 2a by changing the spin speed as the ilywheel moves through'the positions in Figures 1a, 1b, 1c, and ld. Supaxis will be maximum.As ring I' turns and the ilywheel passes through the position in Figure1b, the direction of the torque developed about the power axis willchange. However', the spin speed of the flywheel will be low during thisportion of the cycle about the precession axis, hence the magnitude ofthe torque which is developed in the direction opposite to that inFigure la will Generally stated, during that portion tive, the spinspeed will be high and during the portion when the torque is negative,the spin speed will be low, thus the positive torque will be greater inmagnitude than the negative torque.

The variation of the gyroscopic torque about the ypower axis for thedifferent positions about the precession axis will then take a form suchas that shown in Figure 2b.

The spirit of my invention lies in this nonllinear` cyclical variationof flywheel spin speedl during the processional rotation to obtain avariable torque about the power axis which is greater in one direction.'A number of fiywheels given :this motion and acting together willproduce a A lsmooth, unidirectional torque about the power axis. Manydifferent operative connectors could be devised to give this non-linearcyclical variation. Figure 3 shows diagrammatically one way in whichthis may be done. In Figure 3, the precession member I is rotatablysupported about the precession axis by gimbal 2. Means for rotating theprecession member I at constant speed are not shown. Integral withprecession member I and at the intersection of the power and precessionaxes are three radially projecting shafts 30, each at a right angle tothe precession axis and each spaced from its neighbor about theprecession axis, Rotatably supported on eachshaft extension 3B are threenoncircular flywheels 4a, 4b, and 4c, each having the same shape. Theflywheels are equipped along their non-circular circumference with gearteeth. Attached to gimbal 2 is a gear 32a having teeth meshing with theflywheels 4a, 4b, and 4c. The pitch radius of the flywheels is variablefrom a minimum at point Q as shown on iiywheel 4a to a maximum at pointT which is diametrically opposite from point Q. Cavities 3| are formedin the flywheels in the vicinity of the larger radius to balance theflywheel about the spin axis. The pitch radius of the bevel teeth ongear 32a about the precession axis is constant. However, the teeth ongear 32a are displaced parallel to the precession axis in order to meshproperly with the teeth on the flywheels.

As the precession member I rotates at a constant speed about theprecession axis, it carries the flywheels about the precession axis.Since the gear 32a does not rotate about the precession axis, theiiywheels are forced to rotate about their respective spin axes. Thevariation of the pitch radius of the ywheels causes the spin speed tovary as the flywheels are carried about. At anyposition, the spin speedof any wheel will depend upon its pitch radius to the point of mesh withgear 32a and the precession speed. The number of teeth on each flywheelis the same as that on gear 32a, therefore, the nonlinear variation inspin speed will be cyclical with respect to the rotation of theflywheels o about the precession axis.l When point Q is rpoint T will bethe point of mesh. The developed torque about the power axis due to thegyroscopic effect of flywheel 4a will, therefore, follow a form similarto that in Figure 2b. Each of the other flywheels will contribute asimilar form displaced 120 apart. The gyroscopic torque about the poweraxis from the three fly-wheels combined is shown in Figure 2c. The zerodegree position is that shown in Figure 3 and the successive values arefor the indicated angular displacements of precession member I about theprecession axis in the direction of the arrow in Figure 3. The sum ofthe three effects is a constant unidirectional torque (4a-i-4b-l-4c) asshown in Figure 2c.

For a given angular momentum about the spin axis the effective componentperpendicular to the power axis is maximum when the spin axis isperpendicular to the power axis. In the mechanism shown in Figure 3, themaximum and the minimum spin speeds during the cycle about theprecession axis are attained by each flywheel at the positions when itsrespective spin axis is perpendicular to the power axis, thus thelargest possible average torque is developed for a given precessionspeed. If the gear 32a could be turned a small amount about theprocession axis and rigidly fastened in this new position, each fiywheel would reach its maximum and minimum spin speeds at positions whenits respective spin axis would be at some angle less than 90 withrespect to the power axis. Hence the maximum spin speed would not occurat the position with the maximum component of angular momentum for apositive torque, and the minimum spin speed would not occur at theposition with the maximum component of angular momentum for a negativetorque. The average torque about the power axis would, therefore, bedecreased. It gear 32o; were turned 90 about the procession axis fromthe position shown in Figure 3, the average gyroscopic torque about thepower axis would zero. From this discussion it is seen that it ispossible to control the torque about the power axis by shifting thephase of the non-linear cylical variation of flywheel spin speedwithrespect to the period of rotation of the flywheels about theprecession axis.

Figures 4 and 5 are two views of a preferred embodiment or my invention,showing means for precession and, in addition, means for control of theoutput torque, Figure fi being a partsectional plan and Figure 5 asection along line 5-5 in Figure 4, omitting gear 52. The power inputshaft 2l and the power output or driven shaft t are ccaxially locatedalong the power xis. The stationary housing for the mechanism consistsof a casing 28 and end plate 59, said end plate being attached to saidcasing by some means such as a plurality of screws 53 which would allowdis assembly of end plate 59 from casing 2t when required. The drivenshaft 3 projects through the casing and is rigidly attached or integralwith gimen i, this rigid assembly of shaft a and gimbal 2 beingrotatably supported by anti-friction bearings 'I and 'la within thehousing. A heavy mass of metal 33 rigidly attached or integral withgimbal 2 helps balance the rotating system about the power axis. Inputshaft 2l projects through the gimbal and is rotatably supported byantlfriction bearings 5 and 6 within hub 2 which is integral with gimbal2. Circular bevel gear B is securely attached to the inside end of shaft2l by some means such as key 8. Gear 9 meshes with bevel teeth on acircular gear lil. which is rotatably supported by anti-frictionbearings 25 and 26 on procession shaft I. Procession shaft i isrotatably supported along the precession axis at a right angle to thepower axis by bearings I-l and I9, bearing 36 being mounted in gimbal 2.and bearing I9 being mounted at the outer end of an extension 2li whichis rigidly attached or integral with gimbal 2. In Figure 4, extension 20is cut away to show the gears which are being carried on precessionshaft I. Gear l has internal teeth cut at Il which mesh with a pluralityoi circular planet pinions l2. Each planet pinion I2 is rigidly attachedor integral with a shaft i3 which is rotatably supported along an axisparallel to the procession axis by a bushing I4 within a thickcylindrical disc i5. Disc I5 is rigidly fastened to procession shaft lwhich passes through a circular openingr at the center of said disc bysome means such as key i6. Each pinion I2 also meshes with teeth on acircular gear It which is rotatably supported hy anti-friction bearingsil and. 22 on precession shaft I. Gear I8 also has bevel teeth meshingwith stationary circular ring' bevel gear 23, which is rigidly attachedto casing 28 by some means such ask a plurality of bolts 2t.

Three radially-protecting. shafts are integral with precessicn shaft Iiat the point where the power axis and the procession axis substantiallyintersect.. Each shaft 35i projects out at a right to the precessionaxis and, furthermore, cach shaft extension is displaced about theprocess-'Ion axis from its neighbor. Rotatably mounted on each. shaftextensionis a ywheel 4, having bevelvv teeth distributed about anon-circular circumference at a variable pitch radius as previouslyindicated in Figure 3. Each iiywheel il isl rotatably supported atthe-same distance from the procession axis by bearings 2i and 29 onshaft In Figure 4l, one of the flywheels and its shaft til are omittedto simplify the view. In cach flywheel are cavities tl distributed inthe vicinity of the maximum pitch radius. for balance about the spinaxis. The beve-l teeth of the flywheels mesh with bevel teeth oncircular gear 32, the bevel teeth on gear t2 being displaced parallel tothe precession axis to mesh properly with the iiywheel's. Furthermore,the number of teeth on each flywheel is the same as that on gear 32.Gear 32 is rotatably supported on hub 38 which integral with gimbal 2.Gear t also has internal teeth cut at @il which mesh circular p *non 3e.Pinion 3l! is rigidly attached or inte- 'il with shaft t? which isyparallel to the procession and rotatably supported by bearings Il M,bearing M being mounted in gimbal 2 and bearing M being mounted at theouter end of extension 45 which is rigidly attached or integral withgimbal 2. A circular gear 4l is mounted on a bushing 43 and is rotatablysupported on shaft 3l. Gear d? has bevel teeth at da which mesh with thestationary circular ring bevel gear 35. Gear 35 is rigidly attached tothe casing 2li by some means such as a plurality of bolts 34. Gear 4?also has teeth Ma which mesh with a plurality of circular planet pinions49. Each planet pinion 9 is rigidly attached to or integral with shaft5S which is rotatably supported parallel to shaft 31 in a bushing Ellawithin. disc i8 which has a cavity for each bushing Sila. Centrallyformed in disc 68 is an opening through which shaft 3l passes. Disc 43is rigidly attached to shaft t? by some means such as key 42. Pinions 69also mesh with internal teeth on circular gear 5I. Gear 5I is supportedon bushing lila, which is rotatably supported on shaft 3l. Gear 5I alsohas bevel teeth meshing with bevel teeth on circular ring gear 52. Gear52 is .rotatably supported and confined against end plate 59 by ring 51.Ring 5! is rigidly attached to end plate 59 by some means such as aplurality of bolts 56. Gear 5? also has teeth meshing with circularpinion 5.3 which is rigidly attached to or integral with. control shaft54. Control shaft 54 is mounted parallel to the power axis and isrotatably supported by bushing t5 wi un end plate 59.

.uitable collars and shoulders restrain all rotating members againstendwise displacement as would be readily understood by those skilled inthe art of mechanics.

The operation of the arrangement shown in Figures e and 5 is as follows.lt will be assumed that the input shaft 2l is being driven at a con'-stant speed from some source of power. The rotation of shaft 2I and geara causes gear Ill to rotate about the precession axis. At the beginning,shaft 3 and gimbal 2 are motionless, hence gear I8 is held motionless bystationary gear 23 and gear 32 is held motionless by its attached geartrain as will be explained later. The rota-v tion of gear I actingthrough pinions I2, disc I5 and key I6 causes the precession shaft I torotate about its axis. As precession shaft I rotates, itl carriesflywheels 4 about gear 32 at a constant precessional speed. The variablepitch radius of' the ywheels gives each flywheel the desired cyclicalvariable spin speed. The gyroscopic effect due to the variable spinspeed and precessional rotation of the three iiywheels will develop aconstant unidirectional torque about the power axis. This torque will betransmitted from the flywheels through the shaft extensions 39, and theprecession shaft I to gimbal 2 and driven shaft 3. If the external loadis sufficiently great, the torque developed will not be enough to rotateshaft 3. However, this mechanism will still be capable of exerting atorque on the load for this zero output speed condition, while the primemover can keep rotating at high speed. If the torque developed about thepower axis can overcome the load, shaft 3 and gimbal 2 carryingprecession shaft I and control shaft 37 and their mounted gears will allbegin rotating about the power axis. Since gear I is mounted onprecession shaft I, it will also be carried 4about the power axis, hencethe rotation of gear I0 about the precession axis will change, becominggreater if its rotation about the power axis is in a direction oppositeto that of gear 9, and smaller if it is in the same direction as that ofgear 9. However, as shaft I rotates about the power axis, it will causegear I8,

, which is meshing with stationary gear 23, to rotate about theprecession axis. This motion of gear I8 will act through pinions I2 tocompensate for the change in the speed of gear I0 about the precessionaxis. The speed of disc I about the preecssion axis will, therefore, beconstant regardless of the speed of the driven shaft. Hence, theprecession speed and spin speed of the iiywheels will be independent ofthe speed of the driven shaft and the torque on the driven shaft willremain constant.

Gear 52 can be held stationary by control shaft 54 acting through pinion53 so that when the gimbal 2 is motionless, gear 4'! is held motionlessby stationary gear 35 and gear 5I is held motionless by gear 52.Therefore, pinions 49, disc 48, shaft 31. pinion 39 and hence gear 32are all held motionless during the zero output speed condition. Asdriven shaft 3 and gimbal 2 carrying shaft 3l all commence to rotateabout the power axis, gear 41 is forced to rotate about shaft 31 andgear 5I is also forced to rotate about shaft 37 in a direction oppositeto that of gear 41. While gear 52 is held motionless by the controlshaft 54, the speeds of rotation of gear 41 and gear 5I will be such asto rotate .pinions 49 as if they were merely idlers without compellingdisc 48 to rotate about shaft 3'I. Hence, during rotation of shaft 3 andgimbal 2 about the power axis, gear 32 will still be held from rotatingabout the precision axis by control shaft 54. When control shaft 54 isrotated by an operator, it will cause gear 52 to tLu'n about the poweraxis. This will add or subtract a displacement to the rotation of gear5I depending upon the direction in which the control shaft 54 isrotated. This increment of motion will be transmitted through pinions49, disc 48, shaft 31 and pinion 39 to gear 32. Rotation of gear 32about the precession axis by control shaft 54 will shift the phase ofthe non-linear variation of spin speed with respect to the cycle ofprecession, thus changing the positions at which the maximum and minimumflywheel spin speeds occur in their cycle about the precession axis.This change in position will change the torque on the driven shaft. Atany time while the unit is functioning, the torque on the driven shaftwill be a function of the speed of input shaft 2| and the position ofvcontrol shaft 54 only. The speed of the driven shaft will be a functionof this torque and the load conditions.

In Figure 4, it will be noted that gear 32 has been rotated to theposition for which the torque output of the device is zero. This hasbeen done only to more clearly show the shape of gear 32.

It will be understood that the above description covers only onepreferred embodiment of my invention as shown in Figures 4 and 5. Thespirit of my invention lies in the continuous variation of flywheel spinspeed during a precessional motion of the fiywheels to develop a smooth,unidirectional power output torque. The embodiment of this invention asshown in Figures 4 and 5 contains in addition to the basic idea, thegears I2, I8 and 23 to maintain precession and spin speed independent ofdriven shaft speed, and gears 35, 39, 41, 49, 5I, 52 and 53 t0 controlthe torque on the driven shaft while the driving and the driven shaftare rotating. My invention could Successfully be embodied in aconstruction which omitted either or both of these gear trains. Figure 6is a part-sectional plan showing a simplified embodiment.

In Figure 6, gear I0' is rigidly attached to precession shaft I by somemeans such as a key IIJa. Gear 32 is rigidly attached to gimbal 2 bysome means such as a plurality of screws 32h. In this embodiment, thetorque capacity of the unit could be easily changed by stopping themachine, removing screws 32h, rotating gear 32 to a new position, andreplacing screws 32h. Gear 32 is shown in the zero output torqueposition for the sake of clarity only. This embodiment would have thefeature of automatic and continuous variation of output torque to suitload requirements. As the speed of the driven shaft would change, therotational speed of gear I0 about the precession axis would also change.This would alter the precession and hence the spin speeds of theflywheels, changing the torque developed about the power axis.

The embodiment shown in Figures 4 and 5 merely shows one method ofcontrolling the torque on the driven shaft while the mechanism is inoperation. Different means for doing this could easily be devised andstill fall within the spirit of my invention. Also, the sizes of thegears in the differential gear train which keeps the precession speedindependent of the driven shaft speed could Abe altered to givedifferent desired characteristics of torque on the driven shaft `withdifferent driven shaft speeds. Additional gear trains may be constructedin the mechanism between the power source and the input shaft and/orbetween the driven shaft and the load. Furthermore, the direction ofpower transmission could be reversed, i. e., the driving shaft 2|becoming the driven shaft and the driven shaft 3 becoming the drivingshaft, without departing from the spirit of my invention. In this formthe gyroscopic torque would be developed about the precession axis andtransmitted through gear 9 about the power axis. Other means of varyingthe spin speed during the precession cycle, such as by use of a Scotch 9yoke mechanism, might be used and still fall within the spirit of myinvention.A lslso,y the num-v ber ofv flywheels used need not always bethree such as I have described.

Therefore, while I have illustrated specific forms of the invention, itis to be understood that I do. not. to myself to these exact forms butintend to claim myinvention broadly as defined by the appenced claims.

claim:

l. In a power transmission device, a power input mem-ber, a power outputmember rotatable about an axis, and anoperativc' connection between saidmembers including a gyroscop'ic mass, a structure supporting said massso that it is capable of simultaneously rotating' about a power axiscoincident with the axis of rotation of said power output member,4 rota,Y recession axis perpendicular to said power axis, and

spinning about a spin perpendicular to said .procession a firstoperative connection be tween power input member and said mass forrotating said mass about said pr-ecession axis and a second operativeconnection between said power output member and said mass for spinningsaid mass about said spin axis, said second operative connection beingnon-linear in nature cyclically with respect to the period of rotationof said mass about said procession axis, a control member and an-operative connection between said control member and said secondoperative `connection to shift the phase of the cyclical nonlinearity ofsaid second operative connection with respect to the position of saidmass about said procession axis.

In a power transmission device, a power input member, a power outputmember rotatable about axis, and an operative connection between saidmembers including a plurality of gyroscopic masses, a structuresupporting said masses so that each is capable of simultaneouslyrotating about a power axis coincident with the axis of rotation of saidpower output member, rotating about a precession axis perpendicular tosaid power axis, and about its own spin axis perpendicular to saidprocession axis, the spin axes of said masses being angularly displacedwith respect to one another about said precession axis, a firstoperative connection between said power input member and said masses forrotating said masses about said procession axis and a second operativoconnection between said power output incrnber and said masses forspinning said masses about their respective spin axes, said secondoperative connection being nondinear in nature cyclically with respectto the period of rotation of said masses about said precession axis, anexternal control member and an operative connection between said controlmember and said second operative connection eective to shift the phaseof the cyclical nonn linearity of said second operative connection withrespect to the position of said masses about said procession axis.

il. In a power transmission device, a supporte ing frame, a gimbalmounted therein so as to be rotatable about a power axis, a power outputshaft operatively connected to said gimbal for simultaneous rotationtherewith, a procession shaft rotatably mounted in said gimbal so as toextend perpendicular to said power axis, said shaft defining aprocession axis, a power input shaft, and an operative drivingconnection between said power input shaft and said precassion shaft forrotating the latter, a plurality of 10i` gyroscopic masses mounted onspin shafts and rotatable with respect to spin axes, said spin axesbeing perpendicular to said procession axis and angularly disposed withvrespect to one another about said procession axis, said spin shaftsbeing connected to said precession shaft for Vrotation therewith, eachof said masses having gear teeth distributed along a non-circularoircumference,I and another gear mounted in said girnbalA and rotatableabout said procession axis, said. other gear having, gear teeth formedon an undulating surface, said gear teeth simultaneously meshing with.the gear teeth on all of said masses, whereby rotationfrof said powerinput shaft will cause said masses to rotate about said procession.axis. andy the; mesh between the gear teeth on said masses andthe gear4teeth onV said other gear will cause said masses to spin at varying,speeds cyclically related to their position about the precessicn axis,an external control member and an operative connection between saidcontrol member and said other gear for controllably positioning saidother gear about said procession axis with respect to said gimbal.

(l. The power transmission device 0f claim 3 in which the operativedriving connection be tween said power input shaft and said precessionshaft for rotating the latter comprises a planetary gear unit the outputplanet gear carrior of which is drivingly connected to said precessionshaft, said power input shaft being operatively connected to saidplanetary gear` unit so as to constitute one input thereto, a reactiongear for said planetary gear unit, said reaction gear being operativelyconnected to said gimbal and to said supporting frame.

5. in a power transmission device, a supporting frame, a girnbal mountedtherein so as to be rotatable about a power axis, a power output shaftoperatively connected to said gimbal for simultaneous rotationtherewith, a precession shaft rotatably mounted in said gimbal so as toextend perpendicular to said power axis, said shaft defining aprecession axis, a power input shaft, an operative connection fordriving the procession shaft comprising a planetary gear unit the outputplanet gear carrier of which is drivingly connected to said processionshaft, said power input shaft being operatively connected to saidplanetary gear unit so as to constitute one input thereto, a reactiongear for said planetary gear unit, said reaction gear being operativelyconnected to said girnbal and said supporting frame, a plurality ofgyroscopic masses mounted on spin shafts and rotatable about spin axes,said spin axes being perpendicular to said procession shaft andangularly disposed with respect to one another about the precessionaxis, said spin shafts being connected to said precession shaft forrotation therewith, each of said masses having gear teeth distributedalong a non-circular circumference, and another gear mounted in saidgimbal and rotatable about said precession axis, said other gear havinggear teeth formed on an undulating surface, said gear teethsimultaneously meshing with the gear teeth on all of Said masses.

6. In a power transmission device, a supporting frame, a gimbal mountedtherein so as to be rotatable about a power axis, a power output shaftoperatively connected to said gimbal for simultaneous rotationtherewith, a procession shaft rotatably mounted in said gimbal so as toextend perpendicular to said power axis, said shaft defining aprecession axis, a power input shaft, and a rst operative drivingconnection between said power input shaft and said precession shaft forrotating the latter, a plurality of gyroscopic masses mounted on spinshafts and rotatable with respect to spin axes, said spin axes beingperpendicular to said precession axis and angularly disposed withrespect to one another about said precession axis, said spin shaftsbeing connected to said precession shaft for simultaneous rotationtherewith, and a second operative connection between said power outputmember, and said masses for spinning said masses about their respectivespin axes, said second operative connection being non-linear in naturecyclically With respect to the period of rotation of said masses aboutsaid precession axis.

` 7. VIn the power transmission device of claim 6, a control member andan operative connection between said control member and second 12operative connection effective to shift the phase of the cyclicalnon-linearity of said second operative connection with respect to theposition of said masses about said precession axis.

MARVIN TAYLOR.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,544,834 Gooder July 7, 1925 1,758,252 Gardner May 13, 19302,045,584 Cotanch June 30. 1936 2,052,507 Walton Aug. 25, 1936 2,296,654Stein Sept. 22, 1942 FOREIGN PATENTS Number Country Date 414,693 GreatBritain Aug. 7, 1934

